Certain 7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamides are inhibitors of β-lactamase and, when used in conjunction with β-lactam antibiotics, can be effective for the treatment of bacterial infections, e.g., by overcoming resistance mechanisms. See, for example, International Patent Application Publication Nos. WO2009/091856 and WO2014/200786 which disclose 7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamides and their synthesis through a hydroxylurea intermediate. See also Mangion et al., 2011, Org. Lett. 13:5480-5483 and Miller et al., 2014, Org. Lett. 16:174-177.
U.S. Patent Application Publication No. US2003/0199541 discloses methods for preparing azabicyclic compounds which are useful as medicaments, in particular anti-bacterial agents. International Patent Application Publication No. WO2008/039420 discloses methods for preparing certain 7-oxo-2,6-diazabicyclo[3.2.0]heptane-2-carboxamides which are useful as β-lactamase inhibitors.
International Patent Application Publication No. WO2010/126820 discloses the preparation of alkyl esters of N-protected oxo-azacycloalkylcarboxylic acids. These esters can be used as intermediates in the synthesis of 7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamides and esters. U.S. Patent Application Publication No. 2015/0141401 describes processes and intermediates useful for the synthesis of beta-lactamase inhibitors. Ji et al. (2012, Tetrahedron 68:1359) describe the acid-facilitated debenzylation of N-Boc, N-benzyl double protected 2-aminopyridinomethyl pyrrolidine derivatives.